Loctite on upper main bearing???

My manual is confusing me (oe manual) Have a 1983 4 cyl chryser 90. Manual say to put loctite on outer surface of upper main bearing THEN to press it on the crank??? Then to install crank seals and main bearings then put into crankcase. Why does it need locktite when its being pinched between the case halves??? And if it does why would it say to put it on before its even on the crank. Why does it not say to put loctite on the lower main bearing? Is the loctite necessary?

Re: Loctite on upper main bearing???

Well, you are not alone--you are confusing me!

Did you remove the upper ball bearing? If you did, then don't press a new one on the crankshaft. Put the shaft in the freezer and heat the bearing on top of a 100 watt bulb for about 1/2 hour. Using gloves, take the bearing and drop it onto the shaft. It will slide down all the way and as it cools, lock to the shaft.

Then, when you go to install the crank in the case, you don't need locktite. It is a nice touch to keep the outer shell of the bearing from rotating in the crankcase but you are correct: Unless there is something wrong with the crankcase, the bearing will be squeezed between the two halves. Additionally, the sealer you use between the halves will ooze into the edges and also hold the outer race. And the top seal carrier will also provide a bit of drag to keep it from rotating. The original (Chrysler) upper ball bearings did have a vertical groove in the outer race and could be pinned into the case but I have never seen one pinned that way.

The reason that nothing is mentioned about the bottom bearing is because the two filister head slotted screws below the bottom 3/8 case bolts are there to squeeze the bearing shell between the case halves--even though they do almost nothing--and if I remember correctly, that bearing IS pinned the same as the center two or three bearings.(depending upon 3 or 4 cylinder engine)